Gene Symbol: SAR1
Description: Arf family GTPase SAR1
Alias: Arf family GTPase SAR1
Species: Saccharomyces cerevisiae S288c

Top Publications

  1. Lee M, Orci L, Hamamoto S, Futai E, Ravazzola M, Schekman R. Sar1p N-terminal helix initiates membrane curvature and completes the fission of a COPII vesicle. Cell. 2005;122:605-17 pubmed
    ..Thus, the initiation of vesicle budding by Sar1p couples the generation of membrane curvature with coat-protein assembly and cargo capture...
  2. Kuehn M, Herrmann J, Schekman R. COPII-cargo interactions direct protein sorting into ER-derived transport vesicles. Nature. 1998;391:187-90 pubmed
    ..membrane and soluble cargo proteins destined for transport from the ER in complexes formed in the presence of Sar1 and Sec23/24, a subset of the COPII components, and GTP or GMP-PNP...
  3. Nakano A, Muramatsu M. A novel GTP-binding protein, Sar1p, is involved in transport from the endoplasmic reticulum to the Golgi apparatus. J Cell Biol. 1989;109:2677-91 pubmed
    b>SAR1, a gene that has been isolated as a multicopy suppressor of the yeast ER-Golgi transport mutant sec12, encodes a novel GTP-binding protein...
  4. Oka T, Nakano A. Inhibition of GTP hydrolysis by Sar1p causes accumulation of vesicles that are a functional intermediate of the ER-to-Golgi transport in yeast. J Cell Biol. 1994;124:425-34 pubmed
    The SAR1 gene product (Sar1p), a 21-kD GTPase, is a key component of the ER-to-Golgi transport in the budding yeast...
  5. Sato K, Nakano A. Dissection of COPII subunit-cargo assembly and disassembly kinetics during Sar1p-GTP hydrolysis. Nat Struct Mol Biol. 2005;12:167-74 pubmed
    ..These data suggest a model for the maintenance of kinetically stable prebudding complexes during the Sar1p GTPase cycle that regulates cargo sorting into transport vesicles. ..
  6. Springer S, Schekman R. Nucleation of COPII vesicular coat complex by endoplasmic reticulum to Golgi vesicle SNAREs. Science. 1998;281:698-700 pubmed
    ..The data suggest that transmembrane proteins can be taken up into COPII vesicles by direct interactions with the coat proteins and may play a structural role in the assembly of the COPII coat complex...
  7. Saito Nakano Y, Nakano A. Sed4p functions as a positive regulator of Sar1p probably through inhibition of the GTPase activation by Sec23p. Genes Cells. 2000;5:1039-48 pubmed
    ..To understand how the GTPase cycle of Sar1p is regulated, we screened for multicopy suppressors of sar1 ts mutants and identified SED4...
  8. Barlowe C, Orci L, Yeung T, Hosobuchi M, Hamamoto S, Salama N, et al. COPII: a membrane coat formed by Sec proteins that drive vesicle budding from the endoplasmic reticulum. Cell. 1994;77:895-907 pubmed
    ..Because the overall cycle of budding driven by these two types of coats appears mechanistically similar, we propose that the coat structures be called COPI and COPII. ..
  9. Saito Y, Yamanushi T, Oka T, Nakano A. Identification of SEC12, SED4, truncated SEC16, and EKS1/HRD3 as multicopy suppressors of ts mutants of Sar1 GTPase. J Biochem. 1999;125:130-7 pubmed
    The yeast SAR1 gene encodes a low-molecular-weight GTPase which is essential for the formation of transport vesicles from the endoplasmic reticulum (ER)...

More Information


  1. Matsuoka K, Schekman R. The use of liposomes to study COPII- and COPI-coated vesicle formation and membrane protein sorting. Methods. 2000;20:417-28 pubmed
    ..Therefore, both generation of coated vesicles and protein sorting into the vesicles can be reproduced with liposomes and purified proteins. ..
  2. Supek F, Madden D, Hamamoto S, Orci L, Schekman R. Sec16p potentiates the action of COPII proteins to bud transport vesicles. J Cell Biol. 2002;158:1029-38 pubmed
    ..We propose that Sec16p nucleates a Sar1-GTP-dependent initiation of COPII assembly and serves to stabilize the coat to premature disassembly after Sar1p ..
  3. Barlowe C, Schekman R. SEC12 encodes a guanine-nucleotide-exchange factor essential for transport vesicle budding from the ER. Nature. 1993;365:347-9 pubmed
    ..b>SAR1 was discovered as a multicopy suppressor of the sec12-1ts strain and encodes a GTPase of M(r) 21,000 (21K) also ..
  4. Saito Y, Kimura K, Oka T, Nakano A. Activities of mutant Sar1 proteins in guanine nucleotide binding, GTP hydrolysis, and cell-free transport from the endoplasmic reticulum to the Golgi apparatus. J Biochem. 1998;124:816-23 pubmed
    ..We have obtained mutants of the yeast SAR1 gene, which show several different phenotypes in cell growth and protein transport [Nakano, A. , Otsuka, H...
  5. Bi X, Corpina R, Goldberg J. Structure of the Sec23/24-Sar1 pre-budding complex of the COPII vesicle coat. Nature. 2002;419:271-7 pubmed
    COPII-coated vesicles form on the endoplasmic reticulum by the stepwise recruitment of three cytosolic components: Sar1-GTP to initiate coat formation, Sec23/24 heterodimer to select SNARE and cargo molecules, and Sec13/31 to induce coat ..
  6. Yorimitsu T, Sato K. Insights into structural and regulatory roles of Sec16 in COPII vesicle formation at ER exit sites. Mol Biol Cell. 2012;23:2930-42 pubmed publisher
    ..Here we present evidence that full-length Sec16 plays an important role in regulating Sar1 GTPase activity at the late steps of COPII vesicle formation...
  7. Kodera C, Yorimitsu T, Nakano A, Sato K. Sed4p stimulates Sar1p GTP hydrolysis and promotes limited coat disassembly. Traffic. 2011;12:591-9 pubmed publisher
    ..Although the role of Sed4p in COPII vesicle formation is implied by the genetic interaction with SAR1, the molecular basis by which Sed4p contributes to this process is unclear...
  8. Murakami A, Kimura K, Nakano A. The inactive form of a yeast casein kinase I suppresses the secretory defect of the sec12 mutant. Implication of negative regulation by the Hrr25 kinase in the vesicle budding from the endoplasmic reticulum. J Biol Chem. 1999;274:3804-10 pubmed
    Sec12p is the guanine nucleotide exchange factor of Sar1 GTPase and functions at the very upstream in the vesicle budding reactions from the endoplasmic reticulum (ER)...
  9. Gimeno R, Espenshade P, Kaiser C. SED4 encodes a yeast endoplasmic reticulum protein that binds Sec16p and participates in vesicle formation. J Cell Biol. 1995;131:325-38 pubmed
    ..The importance of Sed4p for vesicle formation is underlined by the isolation of a phenotypically silent mutation, sar1-5, that produces a strong ER to Golgi transport defect when combined with sed4 mutations...
  10. d Enfert C, Barlowe C, Nishikawa S, Nakano A, Schekman R. Structural and functional dissection of a membrane glycoprotein required for vesicle budding from the endoplasmic reticulum. Mol Cell Biol. 1991;11:5727-34 pubmed
    ..Sar1p membrane association was enhanced by elevated levels of Sec12p. These results suggest that the cytoplasmic domain of Sec12p interacts with Sar1p and that the complex may function to promote vesicle formation. ..
  11. Barlowe C. Three-dimensional structure of a COPII prebudding complex. Dev Cell. 2002;3:467-8 pubmed
    ..Crystallographic analysis of a Sec23/24-Sar1 prebudding complex of COPII now provides a molecular view of this GTPase-directed coat assembly mechanism.
  12. Miller E, Antonny B, Hamamoto S, Schekman R. Cargo selection into COPII vesicles is driven by the Sec24p subunit. EMBO J. 2002;21:6105-13 pubmed
    ..Our data suggest that the principle role of Sec24p is to discriminate cargo molecules for incorporation into COPII vesicles...
  13. Chigri F, Sippel C, Kolb M, Vothknecht U. Arabidopsis OBG-like GTPase (AtOBGL) is localized in chloroplasts and has an essential function in embryo development. Mol Plant. 2009;2:1373-83 pubmed publisher
    ..They furthermore corroborate the significance of chloroplast functions for embryo development - an important stage within the Arabidopsis lifecycle...
  14. Kodera C, Yorimitsu T, Sato K. Sec23 homolog Nel1 is a novel GTPase-activating protein for Sar1 but does not function as a subunit of the coat protein complex II (COPII) coat. J Biol Chem. 2014;289:21423-32 pubmed publisher
    ..II (COPII) generates transport carriers from the endoplasmic reticulum (ER) under the control of the small GTPase Sar1. Sec23 is well known as a structural component of the COPII coat and as a GTPase-activating protein (GAP) for Sar1...
  15. Otte S, Barlowe C. The Erv41p-Erv46p complex: multiple export signals are required in trans for COPII-dependent transport from the ER. EMBO J. 2002;21:6095-104 pubmed
  16. Ackema K, Prescianotto Baschong C, Hench J, Wang S, Chia Z, Mergentaler H, et al. Sar1, a Novel Regulator of ER-Mitochondrial Contact Sites. PLoS ONE. 2016;11:e0154280 pubmed publisher
    ..Here we report a previously unanticipated, but conserved role of the small GTPase Sar1 in the regulation of ER-mitochondrial contact site size...
  17. McMahon C, Studer S, Clendinen C, Dann G, Jeffrey P, Hughson F. The structure of Sec12 implicates potassium ion coordination in Sar1 activation. J Biol Chem. 2012;287:43599-606 pubmed publisher
    ..COPII coat assembly is Sec12, a guanine nucleotide exchange factor responsible for activating the small G protein Sar1. Once activated, Sar1/GTP binds to endoplasmic reticulum membranes and recruits COPII coat components (Sec23/24 and ..
  18. Kakoi S, Yorimitsu T, Sato K. COPII machinery cooperates with ER-localized Hsp40 to sequester misfolded membrane proteins into ER-associated compartments. Mol Biol Cell. 2013;24:633-42 pubmed publisher
    ..COPII components and ER-associated Hsp40, Hlj1p, act in the same pathway to sequester EGFP-CFTR into ERACs. Our findings point to an as-yet-undefined role of COPII proteins in the formation of ERACs. ..
  19. Chen E, Frand A, Chitouras E, Kaiser C. A link between secretion and pre-mRNA processing defects in Saccharomyces cerevisiae and the identification of a novel splicing gene, RSE1. Mol Cell Biol. 1998;18:7139-46 pubmed
    ..The secretion defect in each mutant can be suppressed by increasing the amount of SAR1, which encodes a small GTPase essential for COPII vesicle formation from the ER, or by deleting the intron from the ..
  20. Powers J, Barlowe C. Erv14p directs a transmembrane secretory protein into COPII-coated transport vesicles. Mol Biol Cell. 2002;13:880-91 pubmed
    ..Based on these results and further genetic experiments, we propose Erv14p coordinates COPII vesicle formation with incorporation of specific secretory cargo. ..
  21. Lord C, Bhandari D, Menon S, Ghassemian M, Nycz D, HAY J, et al. Sequential interactions with Sec23 control the direction of vesicle traffic. Nature. 2011;473:181-6 pubmed publisher
    ..These events are conserved in mammalian cells. ..
  22. Sato M, Sato K, Nakano A. Evidence for the intimate relationship between vesicle budding from the ER and the unfolded protein response. Biochem Biophys Res Commun. 2002;296:560-7 pubmed
    ..The overexpression of IRE1 suppresses the sec mutants defective in vesicle budding from the ER but not others, highlighting a close relationship between the ER exit and the UPR. ..
  23. Copic A, Latham C, Horlbeck M, D Arcangelo J, Miller E. ER cargo properties specify a requirement for COPII coat rigidity mediated by Sec13p. Science. 2012;335:1359-62 pubmed publisher
    ..Thus, Sec13p may rigidify the COPII cage and increase its membrane-bending capacity; this function could be bypassed when a bst mutation renders the membrane more deformable. ..
  24. Sato K, Nakano A. Reconstitution of coat protein complex II (COPII) vesicle formation from cargo-reconstituted proteoliposomes reveals the potential role of GTP hydrolysis by Sar1p in protein sorting. J Biol Chem. 2004;279:1330-5 pubmed
    ..Furthermore, this GTP hydrolysis decreases the error of cargo sorting. We suggest that GTP hydrolysis by Sar1p promotes exclusion of improper proteins from COPII vesicles. ..
  25. Rein U, Andag U, Duden R, Schmitt H, Spang A. ARF-GAP-mediated interaction between the ER-Golgi v-SNAREs and the COPI coat. J Cell Biol. 2002;157:395-404 pubmed
    ..The mechanisms by which v-SNAREs interact with COPI and COPII coat proteins seem to be different and may play a key role in determining specificity in vesicle budding...
  26. Belden W, Barlowe C. Distinct roles for the cytoplasmic tail sequences of Emp24p and Erv25p in transport between the endoplasmic reticulum and Golgi complex. J Biol Chem. 2001;276:43040-8 pubmed
    ..The Erv25p tail sequence binds COPI and is responsible for returning this complex to the ER. ..
  27. Ligr M, Velten I, Frohlich E, Madeo F, Ledig M, Fröhlich K, et al. The proteasomal substrate Stm1 participates in apoptosis-like cell death in yeast. Mol Biol Cell. 2001;12:2422-32 pubmed
    ..Conversely, Stm1 accumulation induces cell death. In addition we identified five other genes whose overexpression in proteasomal mutants caused similar apoptotic phenotypes. ..
  28. Barlowe C, d Enfert C, Schekman R. Purification and characterization of SAR1p, a small GTP-binding protein required for transport vesicle formation from the endoplasmic reticulum. J Biol Chem. 1993;268:873-9 pubmed
    ..The SAR1 gene was discovered as a multicopy suppressor of a sec12ts strain and encodes a 21-kDa GTP-binding protein also ..
  29. Gemayel R, Chavali S, Pougach K, Legendre M, Zhu B, Boeynaems S, et al. Variable Glutamine-Rich Repeats Modulate Transcription Factor Activity. Mol Cell. 2015;59:615-27 pubmed publisher
    ..Thus, Q-rich repeats are dynamic functional domains that modulate a regulator's innate function, with the inherent risk of pathogenic repeat expansions. ..